A cluster of tumors in which the GPCR LGR5 (a stem cell marker) and GPR64 (an orphan receptor) is overexpressed corresponded to the WNT group of MBs, whereas a cluster of tumors in which the GPCR PTGER4 (a prostaglandin receptor) is overexpressed corresponded to the SHH group of MBs. This evidence concerns the gene PTGER4 and Mobius syndrome.